XOR Operation in an Array

Description

Given an integer n and an integer start.

Define an array nums where nums[i] = start + 2*i (0-indexed) and n == nums.length.

Return the bitwise XOR of all elements of nums.

 

Example 1:

Input: n = 5, start = 0
Output: 8
Explanation: Array nums is equal to [0, 2, 4, 6, 8] where (0 ^ 2 ^ 4 ^ 6 ^ 8) = 8.
Where "^" corresponds to bitwise XOR operator.

Example 2:

Input: n = 4, start = 3
Output: 8
Explanation: Array nums is equal to [3, 5, 7, 9] where (3 ^ 5 ^ 7 ^ 9) = 8.

Example 3:

Input: n = 1, start = 7
Output: 7

Example 4:

Input: n = 10, start = 5
Output: 2

 

Constraints:

• 1 <= n <= 1000
• 0 <= start <= 1000
• n == nums.length

Solution(javascript)

/**
 * @param {number} n
 * @param {number} start
 * @return {number}
 */
const xorOperation = function (n, start) {
  let result = null
  for (let i = 0; i < n; i++) {
    if (result === null) {
      result = start + 2 * i
    } else {
      result ^= start + 2 * i
    }
  }
  return result
}